/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.planner.plan.nodes.exec.common;

import org.apache.flink.api.dag.Transformation;
import org.apache.flink.streaming.api.transformations.OneInputTransformation;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.planner.codegen.CodeGeneratorContext;
import org.apache.flink.table.planner.codegen.ExpandCodeGenerator;
import org.apache.flink.table.planner.delegation.PlannerBase;
import org.apache.flink.table.planner.plan.nodes.exec.ExecEdge;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNode;
import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeBase;
import org.apache.flink.table.runtime.operators.CodeGenOperatorFactory;
import org.apache.flink.table.runtime.typeutils.InternalTypeInfo;
import org.apache.flink.table.types.logical.RowType;

import org.apache.calcite.rex.RexNode;

import java.util.Collections;
import java.util.List;

/**
 * Base {@link ExecNode} that can expand one row to multiple rows based on given projects.
 */
public abstract class CommonExecExpand extends ExecNodeBase<RowData> {

	private final List<List<RexNode>> projects;
	private final boolean retainHeader;

	public CommonExecExpand(
			List<List<RexNode>> projects,
			boolean retainHeader,
			ExecEdge inputEdge,
			RowType outputType,
			String description) {
		super(Collections.singletonList(inputEdge), outputType, description);
		this.projects = projects;
		this.retainHeader = retainHeader;
	}

	@SuppressWarnings("unchecked")
	@Override
	protected Transformation<RowData> translateToPlanInternal(PlannerBase planner) {
		final ExecNode<RowData> inputNode = (ExecNode<RowData>) getInputNodes().get(0);
		final Transformation<RowData> inputTransform = inputNode.translateToPlan(planner);

		final CodeGenOperatorFactory<RowData> operatorFactory = ExpandCodeGenerator.generateExpandOperator(
				new CodeGeneratorContext(planner.getTableConfig()),
				(RowType) inputNode.getOutputType(),
				(RowType) getOutputType(),
				projects,
				retainHeader,
				getClass().getSimpleName());

		final Transformation<RowData> transform = new OneInputTransformation<>(
				inputTransform,
				getDesc(),
				operatorFactory,
				InternalTypeInfo.of(getOutputType()),
				inputTransform.getParallelism());

		if (inputsContainSingleton()) {
			transform.setParallelism(1);
			transform.setMaxParallelism(1);
		}
		return transform;
	}
}
